Light bulb shaped lamp

ABSTRACT

A light bulb shaped lamp (1) according to the present invention includes: a base board (120); an LED chip (110) mounted on the base board (120); a base (190) for receiving power from outside; at least two power-supply leads (140) for supplying power to the LED chip (110); and a globe (170) for housing the base board (120), the LED chip (110), and the power-supply leads (140), the globe being partially attached to the base (190), the base board (120) is translucent, each of the two power-supply leads (140) is extended from a side of the base toward inside of the globe and is connected to the base board (120), and the LED chip (110) is provided between (i) a portion at which one of the two power-supply leads (140) and the base board (120) are connected and (ii) a portion at which the other of the two power-supply leads (140) and the base board (120) are connected.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/360,821 filed Mar. 21, 2019, which is a continuation of U.S.application Ser. No. 15/286,940, filed Oct. 6, 2016, which is acontinuation of U.S. application Ser. No. 13/394,205, filed Mar. 5,2012, which is a National Phase of PCT Patent Application No.PCT/JP2011/004103, filed Jul. 20, 2011, which claims the benefit ofJapanese Patent Application No. 2011-047336, filed Mar. 4, 2011, andJapanese Patent Application No. 2010-162504, filed Jul. 20, 2010. Theentire disclosure of each of the above-identified applications,including the specification, drawings, and claims, is incorporatedherein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to LED light bulbs includinglight-emitting devices, and particularly relates to a light bulb shapedLED lamp having a light-emitting diode (LED).

BACKGROUND ART

Compared to conventional illumination light source, semiconductor lightemitting devices such as LEDs are small, have high efficiency and longlifetime as a light source. Recent market needs for saving energy andresource boosts the demand for light bulb shaped lamps using LEDs(hereafter simply referred to as “LED light bulb”) and lightingapparatuses including the LED light bulbs. Meanwhile, some manufacturersstop manufacturing incandescent light bulbs using filaments (filamentcoils).

For example, the patent literature 1 discloses a conventional LED lightbulb reproducing the shape of conventional filament in an incandescentlight bulb. In the LED light bulb disclosed in the patent literature 1,an optical fiber resembling the shape of a filament is housed in theglobe, an end portion of the LED and the optical fiber are provided nearthe base, and the light emitted from the LED is coupled to the endportion of the optical fiber. With this configuration, the waves of thelight emitted from the LED are guided to the inside of the opticalfiber. This reproduces a state as if the filament emits light.

CITATION LIST Patent Literature

Patent Literature 1 Japanese Unexamined Patent Application Publication(Translation of PCT Application) No. 2008-515158

SUMMARY OF INVENTION Technical Problem

The incandescent light bulb with the filament that can be seen throughthe globe is mainly used for decoration. Luminance that allows directlyviewing the filament and high luminous flux that would brighten up anarea around the light bulb are required for the incandescent light bulb.Accordingly, when replacing the incandescent light bulb with LED lightbulb, luminance and luminous flux equivalent to those of theincandescent light bulb are required for the LED light bulb. Higherefficiency and longer lifetime than those of the incandescent light bulbare required for the LED light bulb as well.

Optical fiber is used in the LED light bulb disclosed in the patentliterature 1. This becomes loss in coupling and loss in waveguide whencoupling and guiding the light emitted from the LED to the opticalfiber, which becomes a bottleneck for increasing efficiency.Furthermore, in order to compensate the coupling loss and waveguide lossfor obtaining high luminous flux, it is necessary to increase theluminous flux from the LED which is the light source. However, it isnecessary to increase the input power to the LED, which causes reductionin efficiency and lifetime.

The present invention has been conceived in order to solve theseproblems, and it is an object of the present invention to provide alight bulb shaped lamp capable of reproducing the simulativelight-emission of the filament in the conventional incandescent lightbulb emitting light without using optical fibers.

Solution to Problem

In order to solve the problems described above, an aspect of the lightbulb shaped lamp according to the present invention is A light bulbshaped lamp comprising: a base board; a light-emitting device mounted onthe base board; a base for receiving power from outside; at least twopower-supply leads for supplying power to the light-emitting device; anda globe for housing the base board, the light-emitting device, and thepower-supply leads, the globe being partially attached to the base, inwhich the base board is translucent, each of the two power-supply leadsis extended from a side of the base toward inside of the globe and isconnected to the base board, and the light-emitting device is providedbetween (i) a portion at which one of the two power-supply leads and thebase board are connected and (ii) a portion at which the other of thetwo power-supply leads and the base board are connected.

With this configuration, it is possible to implement, using thelight-emitting device, a light bulb shaped lamp capable of reproducingthe lighting status similar to an incandescent lamp in which thefilament can be seen through the globe.

Furthermore, in an aspect of the light bulb shaped lamp according to thepresent invention, the base board may be supported by the twopower-supply leads.

With this configuration, it is possible to simplify the componentstructure.

Furthermore, in an aspect of the light bulb shaped lamp according to thepresent invention, a plurality of the light-emitting devices may bemounted in line, and are covered with a sealing material withtranslucent property, and the sealing material may be formed in lineconnecting a gap between the light-emitting devices.

With this configuration, it is possible to protect the light-emittingdevice with the sealing material. Furthermore, by covering thelight-emitting device with the translucent material, twinkling light isemitted when the electric bulb shaped lamp is turned on.

Furthermore, in an aspect of the light bulb shaped lamp according to thepresent invention, the sealing material may include a wavelengthconversion material which absorbs light emitted from the light-emittingdevice and converts a wavelength of the light into another wavelength.

With this configuration, a linear shaped light-emitting part is formed,reproducing the lighting status of the filament in the conventionalincandescent light bulb when the light bulb shaped lamp is turned on.

Furthermore, in an aspect of the light bulb shaped lamp according to thepresent invention, the light-emitting device may not be mounted on asurface of the base board opposite to a surface on which thelight-emitting device is mounted, and a second sealing material may beprovided on the opposite surface, the second sealing material beingprovided over, in plan view, the sealing material on the surface onwhich the light-emitting device is mounted in plan view.

With this configuration, the light emitted from a surface on which nolight-emitting device is mounted (for example, blue light) is convertedinto another color (for example, converted into yellow light), and asynthesized light such as white light is emitted even from a surface onwhich no light-emitting device is mounted.

Furthermore, in an aspect of the light bulb shaped lamp according to thepresent invention, the sealing material may be in zig-zag shape.

With this configuration, it is possible to simulate the shape of thefilament of the conventional incandescent light bulb.

Furthermore, in an aspect of the light bulb shaped lamp according to thepresent invention, a surface of the base board on which thelight-emitting device is mounted may be in a rectangle shape, the twopower supply leads may be connected to shorter sides of the rectangle.

With this configuration, it is possible to simulate the supportingstatus of the filament part of the conventional incandescent light bulb.

Furthermore, in an aspect of the light bulb shaped lamp according to thepresent invention, a plurality of the light-emitting devices are mountedon at least two surfaces of the base board.

With this configuration, it is possible to simulate the state of thefilament of the conventional incandescent light bulb in which filamentsare entwined.

Furthermore, in an aspect of the light bulb shaped lamp according to thepresent invention, two through holes may be formed in the base board,and one of the two power supply leads may pass through one of the twothrough holes, and the other of the two power supply leads may passthrough the other of the two through holes.

With this configuration, the base board can be firmly connected to thepower supply leads.

Furthermore, in an aspect of the light bulb shaped lamp according to thepresent invention, the base board may be made of a hard-brittle materialhaving an emissivity of 0.8 or higher.

With this configuration, it is possible to promote heat dissipation fromthe base board.

Furthermore, in an aspect of the light bulb shaped lamp according to thepresent invention, the base board may be made of translucent ceramic,and the two power-supply leads are copper wires.

With this configuration, it is possible to promote heat dissipation fromthe base board toward the base through the power supply leads.

Furthermore, in an aspect of the light bulb shaped lamp according to thepresent invention, an electronic part electrically connected to thelight-emitting device may be housed in the base.

With this configuration, power is appropriately supplied to thelight-emitting device.

Furthermore, an aspect of the light bulb shaped lamp according to thepresent invention includes a first series-connected group and a secondseries-connected group each of which is a group of a plurality of thelight-emitting devices connected in series, in which the firstseries-connected group and the second series-connected group areelectrically connected in an inverse parallel connection, AC power issupplied to the two power-supply leads, and each of the two power-supplyleads is electrically connected to each end of the inverse parallelconnection.

With this configuration, it is possible to cause the filament part toemit light by the AC power without using the diode for rectification.Accordingly, the circuit configuration is simplified.

Advantageous Effects of Invention

The present invention can reproduce the simulated light-emission stateof the filament in a conventional incandescent light bulb emittinglight. Furthermore, in the present invention, it is not necessary to useoptical fibers. Thus, no coupling loss described above occurs,implementing an LED light bulb with high efficiency and high luminousflux.

Furthermore, since the light-emitting device is covered with the sealingmaterial, the sealing material and the base board becomes thelight-emitting unit, thereby implementing an LED light bulb with highefficiency and high luminous flux.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view of the LED light bulb according to the embodiment1 of the present invention.

FIG. 2A is a diagrammatic perspective view illustrating theconfiguration of the filament part in the LED light bulb according tothe embodiment 1 of the present invention.

FIG. 2B is a cross-sectional view of the filament part in the LED lightbulb according to the embodiment 1 of the present invention(cross-sectional view along X-X′ in FIG. 2A).

FIG. 3 is a cross-sectional view for describing the configuration of theLED chip and the peripheral part of the LED chip in the LED light bulbaccording to the embodiment 1 of the present invention.

FIG. 4 is a diagram illustrating the circuit configuration of a lightingcircuit in the LED light bulb according to the embodiment 1 of thepresent invention.

FIG. 5A is a chart illustrating a light-distribution pattern of the LEDlight bulb according to the embodiment 1 of the present invention inwhich a base board made of translucent polycrystalline alumina ceramic(total transmittance of 90% or higher) is used.

FIG. 5B is a chart illustrating a light-distribution pattern of the LEDlight bulb according to a comparative example in which a base board madeof opaque alumina ceramic is used.

FIG. 6A is a diagrammatic perspective view illustrating theconfiguration of the filament part in the LED light bulb according tothe variation of the embodiment 1 of the present invention.

FIG. 6B is a cross-sectional view of the filament part in the LED lightbulb according to the variation of the embodiment 1 of the presentinvention (cross-sectional view along A-A′ in FIG. 6A).

FIG. 7 is a front view of the LED light bulb according to the embodiment2 of the present invention.

FIG. 8A is top view illustrating the configuration of the filament partin the LED light bulb according to the embodiment 2 of the presentinvention.

FIG. 8B is a diagram illustrating the arrangement of a sealing materialin the filament part of the LED light bulb according to the embodiment 2of the present invention.

FIG. 9 is a diagram illustrating the circuit configuration of a lightingcircuit in the LED light bulb according to the embodiment 2 of thepresent invention.

FIG. 10 is a diagram (diagrammatic perspective view) for describing thevariation 1 of the filament part of the LED light bulb according to theembodiment 2 of the present invention.

FIG. 11 is a diagram (diagrammatic perspective view) for describing thevariation 2 of the filament part of the LED light bulb according to theembodiment 2 of the present invention.

FIG. 12 is a diagram (diagrammatic perspective view) for describing thevariation 3 of the filament part of the LED light bulb according to theembodiment 2 of the present invention.

FIG. 13 is a diagram (top view) for describing the variation 4 of thefilament part of the LED light bulb according to the embodiment 2 of thepresent invention.

DESCRIPTION OF EMBODIMENTS

The following shall describe the light bulb shaped lamp according to theembodiment of the present invention with reference to the drawings.However, the present invention is determined based on the recitation inClaims. Accordingly, among the components in the following embodiments,the components not recited in the independent claim which illustratesthe most generic concept of the present invention are not necessary forsolving the problem of the present invention but included as a part of apreferable embodiment. Note that, the diagrams are schematic diagrams,and illustration is not necessarily strictly accurate.

Embodiment 1

First, the light bulb shaped lamp according to the embodiment 1 of thepresent invention shall be described. The light bulb shaped lampaccording to the embodiment 1 of the present invention is a light bulbshaped lamp in which LED is used as the light source, and is the LEDlight bulb replacing conventional light bulb shaped lamp such asincandescent light bulbs and light bulb shaped fluorescent lamps.

Overall Configuration of LED Light Bulb

The overall configuration of the LED light bulb according to theembodiment 1 of the present invention shall be described with referenceto FIG. 1. FIG. 1 is a top view of the LED light bulb according to theembodiment 1 of the present invention.

As illustrated in FIG. 1, the LED light bulb 1 according to theembodiment 1 of the present invention uses LED chips which aresemiconductor light-emitting devices as the light source. The LED lightbulb 1 includes a filament part 100 composed of the LED chips and otherparts, two power supply leads 140 (141 and 142) for supplying power tothe LED chips, a stem 160, a globe 170, a circuit 180 includingelectronic parts, and a base 190. The filament part 100 is composed ofthe LED chips 110 (not illustrated) and a base board 120. Note that, inFIG. 1, the circuit 180 and the power supply leads 140 placed inside thebase 190 are illustrated in dotted lines.

The filament part 100 is a light-emitting unit (light-emitting module)reproduces the simulated light-emitting property equivalent to thefilament in an incandescent light bulb, and emits light with the powersupplied from the power supply leads 140. The filament part 100 includesa translucent base board 120 on which the LED chips are mounted, and ishoused in the globe 170. In the embodiment 1, the filament part 100 issuspended approximately at the center of the hollow globe 170. Asdescribed above, placing the filament part 100 at the center of theglobe 170 achieves light-distribution property closely similar to theincandescent light bulb using conventional filament coil when the lampis turned on for light emission.

In addition, the filament part 100 is suspended in the globe 170 withthe support of the two power supply leads 140 (141, 142) at the ends ofthe base board 120. More specifically, the filament part 100 is off theinner surface of the globe 170 in the globe 170. The two power supplyleads 140 are supported by the stem 160. The opening 171 of the globe170 is closed by the stem 160. The base 190 is attached to hide theclosed part. The circuit 180 is housed in the base 190. The two powersupply leads 140 (141, 142) extend from the stem 160 to outside of theglobe 170, and are connected to the circuit 180. Among the two powersupply leads 140 (141, 142) connecting the circuit 180 and the base 190,one of the power supply leads 141 is electrically connected to a screwpart 191 on the side surface of the base, and the other power supplylead 142 is electrically connected to the eyelet 192 at the bottom ofthe base. The following is the more detailed description of thecomponents of the LED light bulb 1 according to the embodiment 1.

Filament Part

First, the filament part 100 shall be described with reference to FIGS.2A and 2B. FIG. 2A is a diagrammatic perspective view of the filamentpart in the LED light bulb according to the embodiment 1 of the presentinvention, and FIG. 2B is a cross-sectional view of the filament partalong X-X′ in FIG. 2A.

As illustrated in FIGS. 2A and 2B, the filament part 100 includes aplurality of LED chips 110, a base board 120 on which the LED chips 110are mounted, and a sealing material 130 for sealing the LED chips 110.

The base board 120 is a mounting base board for mounting the LED chips110, and is a long board having a first main surface 125 (front surface)composing the surface on which the LED chips 110 are mounted and asecond main surface 126 (back surface) composing the surface opposite tothe first main surface. A plurality of the LED chips 110 are arranged ina straight line and mounted on the first main surface of the base board120. The filament part 100 is placed with the first main surface onwhich the LED chips 110 are mounted facing toward the top of the globe170.

The base board 120 is composed of a material translucent to visiblelight. The base board 120 is preferably made of a material with highlight transmittance. With this, the light emitted from the LED chip 110transmits inside the base board 120, and is emitted from a part in whichno LED chip 110 is mounted. Accordingly, even when the LED chips 110 aremounted only on the first main surface of the base board 120, the lightis emitted from the second main surface 126 and other parts. Thus, it ispossible to omnidirectionally emit light from the filament part 100 asthe center.

The base board 120 may be made of inorganic material or resin material,and a translucent ceramic board made of alumina or aluminum nitride, atranslucent glass substrate, or a flexible substrate made of flexibletranslucent resin may be used, for example. The base board 120 accordingto the embodiment 1 is made of ceramic composed of translucentpolycrystalline alumina, and is a bar-shaped cuboid 20 mm long, 1 mmwide, and 0.8 mm thick. Accordingly, the shape of the first main surface125 and the second main surface 126 of the base board 120 is a rectanglewith a large aspect ratio. As described above, by making the shape ofthe base board 120 long, it is possible to reproduce the filament of theincandescent light bulb simulated more closely. Note that, the shape andthe size of the base board 120 are examples, and may be in other form orsize.

Power supply terminals 121 and 122 for fixing the power supply leads 140(141, 142) are provided at both ends of the base board 120 in the longerdirection, and metal plating made of gold and others is made on theuppermost surface of the power supply terminals 121 and 122. At thepower supply terminals 121 and 122 on the ends of the filament part 100,the tip of the power supply leads 140 are electrically and mechanicallyconnected by solder. More specifically, the two power supply leads 140(141 and 142) are connected to the shorter sides of the first mainsurface 125 of the rectangle. In the embodiment 1, the base board 120 isattached to the power supply leads 140 such that the first main surface125 on which the LED chips 110 are mounted faces the top of the globe170 (in a direction that the second main surface 126 faces the base). Inaddition, wire bonding pads 123 and 124 electrically connected to thepower supply terminals 121 and 122 are provided on both ends of thefirst main surface 125 of the base board 120.

Twelve LED chips 110 are provided in a straight line between the powersupply terminals 121 and 122 on the first main surface 125 of the baseboard 120. More specifically, the LED chips 110 are provided between apart at which the power supply lead 141 and the base board 120 areconnected and a part at which the power supply lead 142 and the baseboard 120 are connected.

Note that, the base board 120 is preferably made of a material which isnot only translucent but also has high heat conductivity and heatemissivity for increasing the heat radiation property. In this case, itis preferable that the base board 120 is made of a material generallyreferred to as a hard brittle material, such as glass and ceramic. Here,the emissivity is represented by a ratio with respect to heat emissionon black body (full radiator), and has a value between 0 and 1, with 1being the value of black body radiation. The emissivity of glass orceramic is 0.75 to 0.95, and heat emission close to the black bodyradiation is achieved. In terms of practical use, the emissivity of thebase board 120 is preferably 0.8 or higher, and is more preferably 0.9or higher. In addition, when the volume of the filament part 100 issmall compared to the entire lamp and the heat capacity is small, it ispreferable to have a configuration with high emissivity so as todissipate heat.

Next, the detailed description of the LED chip 110 shall be made withreference to FIG. 3. FIG. 3 is a cross-sectional view for illustratingthe LED chip and the configuration around the LED chip in the LED lightbulb according to the embodiment 1 of the present invention.

As illustrated in FIG. 3, the LED chip 110 includes a sapphire board 111and a plurality of nitride semiconductor layers 112 stacked on thesapphire board 111 and each having a different composition, isvertically long, and is 600 μm long, 300 μm wide, and 100 μm thick. Atan end of the LED chip on a surface opposite to the sapphire board 111,a cathode electrode 113, an anode electrode 114, and wire bonding parts115 and 116 are formed.

The LED chip 110 is fixed with the chip mounting part 119 (see FIG. 2B)of the base board 120 by a translucent chip bonding material 118 suchthat the surface on the sapphire board 111 faces the first main surface125 of the base board 120. Silicone resin containing a filler made ofmetal oxide may be used as the chip bonding material 118. Note that,using translucent material as the chip bonding material 118 reduces theloss of light emitted from the surface of the LED chip 110 on thesapphire board 111 side and side surfaces of the LED chip 110, andprevents a shadow blocked by the chip bonding material 118. In addition,the LED chips 110 are electrically connected by a gold wire 117. Withthis, the 12 LED chips 110 are connected in series. The LED chips 110 atthe ends of the LED chips 110 connected in series are electricallyconnected the wire bonding pad parts 123 and 124 that are electricallyconnected by the gold wire 117 to the feeder terminals 121 and 122provided at the ends of the base board 120. Note that, in the embodiment1, one power supply terminal 121 is a cathode power supply terminal, andthe other power supply terminal 122 is an anode power supply terminal.

The LED chip 110 according to the embodiment 1 is a bare chip whichemits visible light in one color, and a blue LED chip which emits bluelight when energized may be used, for example. Note that, in theembodiment 1, an example in which 12 LED chips 110 are mounted isillustrated. However, the number of the LED chips 110 may be determinedappropriately depending on the usage. For example, as a replacement fora miniature light bulb, only one LED chip may be used.

The LED chips 110 and the gold wire 117 are covered with the translucentsealing material 130 in a straight line shape. The sealing material 130is a phosphor containing resin made of a resin containing phosphorparticles which are wavelength conversion material, and converts thewavelength (converts color) of light emitted from the LED chip 110 tolight with another wavelength, and seals the LED chip 110 for protectingthe LED chip 110. In the embodiment 1, the sealing material 130 isformed in a straight line shape covering all of the LED chips 110arranged in a straight line.

More specifically, translucent resin such as silicone resin may be usedas the sealing material 130, and the sealing material 130 is composed ofthe translucent resin dispersed with phosphor particles (notillustrated) and light-diffusion material (not illustrated). The sealingmaterial 130 with the configuration described above is formed by thefollowing two processes, for example. First, in the first process, thesealing material 130 which is an uncured paste including the wavelengthconversion material is applied in a continuous straight line on the rowof the LED chips 110 by a dispenser. Next, in the second process, theapplied paste of sealing material 130 is cured. The cross-section of thesealing material 130 formed as described above is dome-shaped, and is 1mm wide and 0.2 mm high. Note that, it is preferable that the width ofthe sealing material 130 is approximately the same as the width of thebase board 120.

Note that, the wavelength conversion material included in the sealingmaterial 130 may be a yellow phosphor such as (Sr, Ba)₂SiO₄:Eu²⁺,Sr₃SiO₅:Eu²⁺, for example. Alternatively, the wavelength conversionmaterial may be a green phosphor such as (Ba, Sr)₂SiO₄:Eu²⁺,Ba₃Si₆O₁₂N₂:Eu²⁺. Alternatively, the wavelength conversion material maybe a red phosphor such as CaAlSiN₃:Eu²⁺, Sr₂(Si, Al)₅(N, O)₈:Eu²⁺. Thesealing material 130 may not be necessarily be made of silicone resin,and may be made of an organic material such as fluorine series resin oran inorganic material such as a low-melting-point glass or a sol-gelglass. Since the inorganic materials are more highly resistant to heatthan the organic material, the sealing material 130 made of inorganicmaterial is advantageous for increasing luminance.

As phosphor particles, when the LED chip 110 is a blue LED chip whichemits blue light, a material which absorbs part of the blue light andconverts the wavelength of the light into another wavelength is used.For example, YAG series yellow phosphor particles such as (Y,Gd)₃Al₅O₁₂:Ce³⁺, Y₃Al₅O₁₂:Ce³⁺ may be used in order to obtain whitelight from the blue light. With this, part of the blue light emittedfrom the LED chip 110 is converted into yellow light by wavelengthconversion of the yellow phosphor particles included in the sealingmaterial 130. The blue light which is not absorbed by the yellowphosphor particles and the yellow light obtained by the wavelengthconversion of the yellow phosphor particles are diffused and mixed inthe sealing material 130, and is emitted as white light from the sealingmaterial 130.

Particles such as silica are used as the light diffusion material. Inthe embodiment 1, the translucent base board 120 is used. Thus, thewhite light emitted from the line-shaped sealing material 130 transmitsthe inside of the base board 120, and is emitted from the back surfaceand the side surfaces of the base board 120. As described above, thesealing material 130 including the wavelength conversion material isarranged in line on one of the main surfaces of the bar-shaped baseboard 120. Thus, the base board 120 appears shining like a filament ofthe conventional incandescent light bulb from any surface of the baseboard 120 when the light bulb shaped lamp 1 is turned on.

In addition, the sealing material 130 including the wavelengthconversion material may be arranged on a surface of the base board 120on which the LED chip 110 is not mounted. More specifically, as in theembodiment 1, in a configuration in which the LED chip 110 is mounted onthe first main surface 125 of the base board 120 and the LED chip 110 isnot mounted on the second main surface 126 opposite to the first mainsurface 125, the sealing material 130 (the second sealing material) isformed on the second main surface 126, in addition to the sealingmaterial 130 (first sealing material) on the first main surface. Withthis, the blue light emitted from the second main surface 126 on whichthe LED chip 110 is not mounted is converted into yellow light and whitelight is synthesized. Accordingly, it is possible to set the color oflight emitted from the second main surface 126 on which the LED chip 110is not mounted closer to the color of light directly emitted from thesealing material 130 on the first main surface 125, allowing emission ofwhite light from both surfaces of the base board 120. As a result, alight-distribution property even more closely similar to theincandescent light bulb can be achieved.

In this case, it is preferable that the sealing material 130 formed onthe second main surface 126 is formed over, in plan view, the sealingmaterial 130 formed on the first main surface 125 (in a directionorthogonal to the first and second main surfaces). With this, it ispossible for the light from the LED chip to effectively enter thesealing material 130 on both of the main surfaces.

Note that, the wavelength conversion material included in the sealingmaterial 130 may be a yellow phosphor such as (Sr, Ba)₂SiO₄:Eu²⁺,Sr₃SiO₅:Eu²⁺, for example, in addition to the YAG phosphor.Alternatively, a green phosphor such as (Ba, Sr)₂SiO₄:Eu²⁺,Ba₃Si₆O₁₂N₂:Eu²⁺ may also be used. Alternatively, a red phosphor such asCaAlSiN₃:Eu²⁺, Sr₂(Si, Al)₅(N, O)₈:Eu²⁺ may be used.

The sealing material 130 may not be necessarily be made of siliconeresin, and an organic material such as fluorine series resin or aninorganic material such as a low-melting-point glass or a sol-gel glassmay be used as the sealing material other than the silicone resin. Sincethe inorganic materials are more highly resistant to heat than theorganic material, the sealing material 130 made of inorganic material isadvantageous for increasing luminance.

Power Supply Leads and Stem

The two power supply leads 140 (141 and 142) are power supply wires forsupplying power to cause the LED chip 110 in the filament part 100 toemit light. Each of the power supply leads 141 and 142 is a compositewire including an internal lead wire, a Dumet wire and an external leadwire joined in this order. The two power supply leads 141 and 142 havestrength enough to support the filament part 100, and support thefilament part 100 such that the filament part 100 is suspended at aconstant position in the globe 170.

In each of the power supply leads 141 and 142, the internal lead wire isan electric wire extending to the inside of the globe 170, and isextended from the stem 160 toward the filament part 100. The externallead wire is an electric wire extending to outside of the globe 170, andis extended from the circuit 180 toward the stem 160. Metal wire mainlycontaining copper (copper wire) may be used as the internal lead wireand the external lead wire. The Dumet wire is an electric wire sealedinside of the stem 160. The internal lead wire is connected to the powersupply terminals 121 and 122 on the base board 120, and the externallead wire is connected to the output terminal 182 in the circuit 180which shall be described later.

The stem 160 is provided from the opening 171 of the globe 170 towardthe inside of the globe 170. More specifically, the stem 160 is formedas a rod-shaped extending part having one end extended in the proximityof the filament part 100. More specifically, the stem 160 according tothe embodiment 1 is a component with a shape as if the stem used forconventional incandescent light bulb is extended toward the inside ofthe globe 170. Note that, the stem 160 may be a stem used for a commonincandescent light bulb.

The end portion of the stem 160 on the base side is joined to theopening 171 of the globe 170 so as to close the opening 171. Asdescribed above, part of the each of the power supply leads 141 and 142are sealed in the stem 160. As a result, the filament part 100 inside ofthe globe 170 is electrically connected to the circuit 180 outside,while keeping the globe 170 airtight. Accordingly, with the LED lightbulb 1, it is possible to prevent water or vapor from entering the globe170 for a long period of time, and to prevent degradation of thecomponents of the filament part 100 or degradation of the connectingpart of the filament part 100 and the power supply leads 140 due tomoisture. Note that, each of the power supply leads 140 are notnecessarily a composite wire, but a single wire composed of a singlemetal wire.

The stem 160 is made of soft glass transparent to visible light. Withthis, the LED light bulb 1 can prevent the loss of light emitted fromthe filament part 100 due to the stem 160. The LED light bulb 1 can alsoprevent the shadow formed by the stem 160. Furthermore, white lightemitted from the filament part 100 illuminates the stem 160. Thus, thelight bulb shaped lamp 1 can achieve visually superior appearance. Notethat, the stem 160 may not have to close the opening 171 in the globe170, and may be attached to a part of the opening 171.

Note that, the power supply lead 140 is preferably metal wire containingcopper with high heat conductivity. With this, it is possible toactively dissipate heat generated at the filament part 100 to the base190 through the power supply lead 140. Furthermore, in the embodiment 1,an example in which two power supply leads 140 are included isillustrated. However, it is not limited to this example. For example,when multiple filament parts are housed in the globe and power issupplied to each of the filament parts, each of the filament parts maybe supported by separate power supply lead. Note that, each of the powersupply leads 140 are not necessarily a composite wire, but a single wirecomposed of a single metal wire.

Globe and Stem

The globe 110 has a shape with one end closed in a spherical shape, andthe other end has the opening 171. In other words, the shape of theglobe 170 is that the opening 171 provided in a part of hollow sphere isnarrowed down while extending away from the center of the sphere. In theembodiment 1, the shape of the globe 170 is Type A (JIS C7710) which isthe same as a common incandescent light bulb.

The globe 170 is a hollow translucent component which houses thefilament part 100 inside, and emits the light emitted from the filamentpart 100 to outside of the lamp. In the embodiment 1, the globe 170 is ahollow glass bulb made of transparent silica glass, and the filamentpart 100 arranged at the center of the globe 170 can be seen fromoutside of the globe 170. With this configuration, the loss of the lightemitted from the filament part 100 due to the globe 170 can besuppressed. In addition, with the filament part 100 arranged at thecenter of the spherical globe 170, the omnidirectionallight-distribution property is achieved when the light bulb shaped lamp1 is turned on.

Note that, the shape of the globe 170 does not have to be Type A. Forexample, the shape of the globe 170 may be Type G or Type E, and may beappropriately selected depending on the usage. The globe 170 does nothave to be transparent, and diffusion treatment such as a milky whitediffusion film formed by applying silica may be performed.Alternatively, the globe 170 may be colored in red, yellow, or othercolors, or a pattern or picture may be drawn thereon. Alternatively, theglobe 170 does not have to be made of silica glass. The globe 170 may bemade of transparent resin such as acrylic. Forming the globe 170 withglass as described above allows the globe 170 to be highly resistant toheat.

Circuit and Base

The circuit 180 is a lighting circuit for causing the LED chip 110 inthe filament part 100 to emit light, and is housed in the base 190. Morespecifically, the circuit 180 includes a plurality of circuit elementsand a circuit board on which the circuit elements are mounted. In theembodiment 1, the circuit 180 converts the AC power received from thebase 190 into the DC power, and the DC power is supplied to the LED chip110 through the two power supply leads 140.

FIG. 4 is a diagram illustrating the circuit configuration of thelighting circuit in the LED light bulb according to the embodiment 1 ofthe present invention. As illustrated in FIG. 4, the circuit 180 in theembodiment 1 includes, as electronic parts (circuit elements), a diodebridge 183 for rectification, a capacitor 184 for smoothing, and aresistor 185 for adjusting current.

Here, input terminals of the diode bridge 183 are input terminals 181 ofthe circuit 180, and an end of the capacitor 184 and an end of theresistor 185 are output terminals 182 of the circuit 180. Furthermore,the input terminals 181 are electrically connected to the base 190. Morespecifically, one of the input terminals 181 is connected to the screwpart 191 on the side surface of the base, and the other of the inputterminals 181 is connected to the eyelet 192 at the bottom of the base.The output terminals 182 of the circuit 180 are connected to theexternal lead wire of the power supply lead 140. More specifically, theoutput terminals 182 are electrically connected to a row of LED chips186 (series-connected group) including the LED chips 110 connected inseries.

Note that, the LED light bulb 1 does not have to include the circuit180. For example, when the DC power is directly supplied from a lightingequipment or a cell, the LED light bulb 1 does not have to include thecircuit 180. In this case, one of the external lead wires is connectedto the screw part 191, and the other of the external lead wires isconnected to the eyelet 192. Note that, the circuit 180 is not limitedto a smoothing circuit, but may be an appropriately selected combinationof a light-adjusting circuit, a voltage booster, and others.

The base 190 is provided at the opening 171 of the globe 170. Morespecifically, the base 190 is attached to the globe 170 using anadhesive such as cement to cover the opening 171 of the globe 170. Inthis embodiment, the base 190 is an E26 base. The LED light bulb 1 isattached to a socket for E26 base connected to the commercial AC powersource for use.

Note that, in the embodiment 1, an example using an E26 base isdescribed. However, it is not limited to this example, and the size andthe shape of the base may be appropriately selected depending on theusage. For example, an E17 base or others may be used as the base 190.In addition, the base 190 does not have to be a screw base, and may be abase in a different shape such as a plug-in base. Alternatively, thebase 190 is directly attached to the opening 171 of the globe 170.However, it is not limited to this example. The base 190 may beindirectly attached to the globe 170. For example, the base 190 may beattached to the globe 170 through resin components such as a resin case.In this configuration, the circuit 180 and others may be housed in theresin case, for example.

Light Distribution Pattern

Next, as an example of the effects achieved by the base board 120 in theLED light bulb 1 according to the embodiment 1 of the present invention,light-distribution patterns of the LED light bulbs shall be describedwith reference to FIGS. 5A and 5B. FIG. 5A is a chart illustrating alight-distribution pattern of the LED light bulb 1 according to theembodiment 1 of the present invention in which a base board made oftranslucent polycrystalline alumina ceramic having a total transmittanceof 90% or higher is used. FIG. 5B is a chart for comparison with FIG.5A, and illustrates a light-distribution pattern of the LED light bulbaccording to a comparative example in which a base board made of opaquealumina ceramic is used. Note that, the configurations of the LED lightbulbs used for the charts in FIGS. 5A and 5B are identical to theembodiment 1 except for the material composing the base board. In bothcharts, the light intensity is normalized using the light intensity ofan angle having the highest emission intensity. Zero degree is directedtoward the globe, and 180 degrees are directed toward the base. In thisconfiguration, since the light is blocked by the metal base, no light isemitted to the 180-degree direction toward the base. Usually, an LEDlight bulb is attached to the ceiling. In this case, the globe is on thelower side, and the base is on the upper side (ceiling side).

According to the light-distribution pattern of the LED light bulb 1according to the embodiment 1 using a translucent base board illustratedin FIG. 5A, the light from the LED light bulb 1 is strongly emitted inthe 20-degree direction on the globe side and 150-degree direction onthe base side, which indicates a wide distribution angle of light. Incontrast, according to the light-distribution pattern of the LED lightbulb according to a comparative example using an opaque base boardillustrated in FIG. 5B, the light from the LED light bulb is stronglyemitted in 0-degree direction on the globe side. However, the light issparsely emitted toward the 150-degree direction on the base side, andthe intensity of the light is merely approximately 20% of the highestintensity. Furthermore, an emission angle set to be an angle at whichthe intensity of light is half the highest intensity is approximately110 degrees in the light emitted from the LED light bulb in FIG. 5A, andis narrow in the radiation angle of the light emitted from the LED lightbulb in FIG. 5B, at approximately 70 degrees. As described above, theLED light bulb in FIG. 5A can achieve wider light distribution anglethan the distribution angle of the LED light bulb in FIG. 5B, and alight-distribution pattern closer to that of the incandescent light bulbwith which the filament can be seen from any direction is achieved. Notethat, the direction at which the emission intensity on the globe side ofthe LED light bulb in FIG. 5A should be 0 degree, but is 20 degrees.This is probably because the base board 120 is slightly tilted.

Variation of Filament Part

Next, a variation of the LED light bulb according to the embodiment 1 ofthe present invention shall be described with reference to FIGS. 6A and6B. FIG. 6A is a diagrammatic perspective view of the filament part inthe LED light bulb according to the variation of the embodiment 1 of thepresent invention. FIG. 6B is a cross-sectional view of the filamentpart in the LED light bulb along A-A′ in FIG. 6A.

The LED light bulb according to this variation is different from the LEDlight bulb according to the embodiment 1 in the configuration of thefilament part, and the rest of the configuration is identical.Accordingly, in this variation, the filament part 200 shall be mainlydescribed. The filament part 200 according to the variation includes atranslucent tabular base board 220 and a plurality of rows of LED chips210.

In this variation, the base board 220 is composed of ceramic made ofaluminum nitride, and is a tabular board which is a rectangle 20 mmlong, 10 mm wide, and 0.8 mm thick. Two through holes 221 and 222 areprovided in the base board 220. The two through holes 221 and 222 areprovided at the diagonal ends of the base board 220, and the powersupply leads 140 (141 and 142) passes through the two respective throughholes and fixed with solder. More specifically, the power supply lead141 passes through one of the through holes 221, and the power supplylead 142 passes through the through hole 222. The leads and the throughholes are electrically and mechanically connected with solder.

Furthermore, 30 LED chips 210 which emit violet light are mounted on thefirst main surface 225 of the base board 220. The LED chip 210 iscomposed as three rows of LED chip rows, and one LED chip row includes10 LED chips 210. A part of the metal line pattern 223 plated with goldon the surface is a chip mounting part. The LED chip 210 in thevariation is mounted by a process known as flip chip bonding with whichthe cathode electrode and the anode electrode of the LED chip 210 areconnected to the chip mounting part. Each of the 10 LED chips 210included in a row is connected in series, and the three rows areconnected in series with one another. In other words, all of the 30 LEDchips 210 are connected in series. Note that, the metal line pattern 223may be formed using a transparent conductive material such as indium tinoxide (ITO). By having the metal line pattern 223 made of a transparentconductive material allows reducing the loss due to light absorptioncompared to the case in which the light-blocking metal material is used.In addition, the shadow caused by blocked light does not appear either.

Each of the rows of LED chips of the LED chips 210 is sealed in line bythe sealing material 230 including the wavelength conversion material.With this, it is possible to reproduce the LED light bulb as if thereare three filaments. In this variation, the aluminum nitride composingthe base board 220 is clear and transparent. Thus, when viewed from thesecond main surface 226 side opposite to the first main surface 225 onwhich the LED chip 210 is mounted, it is possible to view the shape ofthe sealing material 230 clearly. As in this variation, since thefilament part is composed of a plurality of LED chip rows (seriesconnected group), each row can be easily recognized from an oppositemain surface side on which the LED chips are not mounted.

Note that, when the LED chip 210 which emits violet light is used as inthis variation, the filament part 200 which emits white light can beachieved by using blue phosphor, green phosphor, and red phosphor as thewavelength conversion material included in the sealing material 230.

In addition, the power supply leads 140 support the filament part 200 atthe diagonal parts of the base board 220 in a square in this variation.However, it is not limited to this example. Alternatively, the filamentpart 200 may be supported at the central part of opposite two sides ofthe rectangle base board 220, or supported at the both ends of one side.In particular, when the base board 220 is placed vertically facing themain surface of the base board on which the LED chip is mounted towardthe side part of the globe 170, the part supporting the base board 220is located at the stem side. Thus, it is possible to shorten the lengthof the power supply lead 140.

Embodiment 2

Next, an LED light bulb 2 according to the embodiment 2 of the presentinvention shall be described with reference to FIGS. 7 to 9. FIG. 7 is afront view of the LED light bulb according to the embodiment 2 of thepresent invention.

As illustrated in FIG. 7, the LED light bulb 2 according to theembodiment 2 of the present invention is different form the LED lightbulb 1 according to the embodiment 1 in that a spherical (Type G) globe370 is used, that the LED chips 310 are mounted on both surfaces of thebase board 320, and that the two rows of LED chips (series connectedgroup) that were connected in series are inversely connected inparallel.

FIG. 8A is a top view of the filament part 300 in the embodiment 2. Thefilament part 300 is formed as follows: a plurality of LED chips 310 arearranged in a zigzag line and mounted on translucent base board 320; thesealing material 330 including the wavelength conversion material isapplied in zigzag shape along the LED chips 310 arranged in zigzag in anarea surrounded by the broken line in FIG. 8A. The LED chips 310 arelocated at the inflection points of the zigzag shape. By shaping thesealing material 330 in a shape other than a straight line gives varietyto the shape of the filament part.

In addition, in the embodiment 2, the LED chips 310 are arranged inzigzag on both sides of the base board 320. The zigzag shaped sealingmaterial 330 is applied on the LED chips 310 on both surfaces. In thiscase, the sealing materials 330 located on one of the main surfaces(first main surface) and on the other of the main surfaces (second mainsurface) are preferably formed such that the zigzag shapes cross eachother. With this configuration, when viewing the base board 320 from oneof the main surfaces, the sealing material 330 on the other main surfacecan be seen through. With this, the appearance of two entwined filamentscan be reproduced. This configuration shall be described with referenceto FIG. 8B. FIG. 8B is a diagram illustrating the arrangement of thesealing material 330 according to the embodiment 2. In FIG. 8B, thearrangement of the sealing material 330 on one of the main surfaces ofthe base board 320 and the other of the main surfaces of the base board320 is illustrated in the broken line 333 and the solid line 334.

Note that, in the embodiment 2, the LED chips are arranged on bothsurfaces of one base board. However, it is not limited to this example.For example, two boards on which the LED chips are mounted only on onemain surface are prepared and the other main surfaces on which no LEDchip is mounted are bonded. With this, the base board on which the LEDchips are mounted on both surfaces can be made. In this case, the sameeffects as the embodiment described above can be achieved.

FIG. 9 illustrates the circuit configuration of the circuit 380 used forthe LED light bulb according to the embodiment 2. As illustrated in FIG.9, in the LED chip row 385 (first series connected group) arranged onone of the main surfaces and the LED chip row 386 (second seriesconnected group) arranged on the other of the main surfaces, the LEDchips in the rows of the LED chips are connected in series. Furthermore,the LED chip row 385 and the LED chip row 386 are electrically connectedin inverse parallel connection. Furthermore, one of the connecting partson which one end of the LED chip row 385 and the one end of the LED chiprow 386 are connected, and the other connecting part on which the otherend of the LED chip row 385 and the other end of the LED chip row 386,that is, both ends of the inverse parallel connection are connected tothe power supply terminals 321 and 322, and electrically connected tothe power supply leads 341 and 342 (in FIG. 7). Note that, the LED chipsthat are side-by-side belong to different LED chip rows (seriesconnected group).

In the circuit 380, the input terminals 381 are electrically connectedto the base 390, and the output terminals 382 are electrically connectedto the power supply terminals 321 and 322 in the filament part 300through the power supply leads 340 (341, 342) in the stem 360. With theconfiguration described above, AC power is supplied from the base 390 tothe power supply lead 340, and AC power is supplied to the ends of theinverse parallel connection. With this, in one cycle, one of the LEDchip rows (for example, the LED chip row 385) is turned on; the other ofthe LED chip rows (for example, the LED chip row 386) is turned off. Andit is reversed in the next cycle; thereby the two LED chip rows 385 and386 keep alternately blinking. Accordingly, in the embodiment 2, thelighting circuit can be configured without using electronic parts forconverting the AC power to the DC power such as a diode bridge forrectification. This allows composing the circuit only with the resistor383 for adjusting current, simplifying the circuit configuration.

Note that, in the embodiment 2, the power supply leads 340 (341, 342)are attached to the base board 320 in a direction that both of the mainsurfaces of the base board 320 on which the LED chips 310 are mountedfacing the side part of the globe 370. Note that, the direction of theattachment of the power supply leads 340 (341 and 342) on the base board320 may be appropriately determined depending on the design of the LEDlight bulb. In addition, in the embodiment 2, the filament part 300 isarranged in a direction that the rows of the LED chips 310 composing thefilament part 300 crosses the central axis of the globe 370. Thedirection may be appropriately determined depending on the design of theLED light bulb. For example, the filament part 300 may be arranged inparallel with or oblique to the central axis of the globe 370.

As described above, in the LED light bulb 2 according to the embodiment2 of the present invention, the light-distribution pattern with a widelight-distribution angle can be achieved, achieving the omnidirectionallight-distribution property close to that of the incandescent lightbulb, in the same manner as the embodiment 1.

Variation of Filament Part

Next, a variation of the LED light bulb according to the embodiment 2 ofthe present invention shall be described with reference to FIGS. 10 to13. FIGS. 10 to 13 are diagrams for illustrating the variations 1 to 4of the filament part in the LED light bulb according to the embodiment 2of the present invention. Note that, for simplifying the description,illustration of the LED chips and the power supply terminals is omittedin these diagrams. Note that, the configuration of the sealing materialis the same as described above, and the sealing material includes thewavelength conversion material.

In the filament part 400 in the variation 1 illustrated in FIG. 10,three translucent base boards 420 (421, 422, and 423) on which the LEDchips are mounted compose three side faces of a triangle pole, and theentire triangle pole is covered with the sealing material 430 includingthe wavelength conversion material, forming a cylindrical light-emittingunit as a whole. As described above, the filament part 400 according tothe variation 1 reproduces the shape of the cylindrical filament.

This configuration is advantageous because the power supply leads (notillustrated) may be inserted and fixed in the inner area 425 of thetriangle pole surrounded by the three base boards 421, 422, and 423.With this, it is possible to actively radiate the heat generated at theLED chip through the power supply leads.

The filament part 500 in the variation 2 illustrated in FIG. 11 iscomposed of three translucent base boards 520 (521, 522, and 523) onwhich the LED chips are mounted are arranged such that the cross-sectionis U-shaped with all corners in straight angles.

This configuration is advantageous because the LED chip mounted surfaceof the base board 522 in the middle is arranged facing the top side ofthe globe. In addition, the LED chip mounted surfaces of the base boards521 and 523 on both sides are arranged facing the side surface of theglobe. With this configuration, the sealing material 530 can berecognized from any direction. With this, the light-emission shape ofthe filament part 500 is even more close to the light-emission shape ofthe filament of the incandescent light bulb when emitting light.

The filament part 600 according to the variation 3 illustrated in FIG.12 is composed by arranging the LED chips and the sealing material 630wound around the translucent polygonal column base board 620.

The configuration is advantageous because the shape of the filament ofthe conventional incandescent light bulb, that is, a spring shape can bereproduced.

The filament part 700 according to the variation 4 in FIG. 13 iscomposed by arranging the LED chips and the sealing material 730 in aring on the circular translucent base board 720.

Note that, the shape of the arrangement of the LED chips and the sealingmaterial 730 is not limited to a circular ring, but may be a shape thatcannot be achieved by the filament of the conventional incandescentlight bulb such as square, star, characters, graphic, signs, or cartooncharacters.

In addition, the shape of the base board 720 may also have a variety notonly square or circle, but also star, characters, graphic, signs, orcartoon characters.

Other Variation of Filament Part and Others

The light bulb shaped lamp according to the present invention has beendescribed above based on the embodiments and variations. However, thepresent invention is not limited to the embodiments and others.

In the embodiments the filament part is configured to emit white lightusing the LED chips and the sealing material including the wavelengthconversion material as an example. However, it is not limited to thisexample.

For example, the filament part can be configured with yellow to amberLED chips along with translucent sealing material that does not includethe wavelength conversion material. Light bulb with low luminous flux isgenerally used for purposes that does not require high color rendition.For these purposes, the light from incandescent light bulb can bereproduced using only the light from the LED chip.

Needless to say, the color of light emitted from the LED chip, whetheror not the wavelength conversion material is used, or the type of thewavelength conversion material may also be selected appropriately.

For example, a configuration in which LED chips of light's three primarycolors, i.e., blue, green, and red are used to obtain white light, aconfiguration in which LED chips having a wavelength from blue-violet toa near-ultraviolet range, and phosphors of the three primary colors,i.e., blue, green, and red are used to obtain white light, or aconfiguration in which light in a single color such as blue only, greenonly, or red only is used is possible as a configuration of the filamentpart.

In addition, although LED is used as an example of the light-emittingdevice in the embodiments, the light-emitting device may be asemiconductor laser, organic electro luminescence (EL), or inorganic EL.

The LED light bulb according to the embodiments and the variations maybe attached to the lighting equipment provided on the ceiling of a room,and can be implemented as a lighting apparatus. The lighting apparatusincludes the LED light bulb and the lighting equipment (light-upequipment). The lighting equipment includes an equipment body attachedto the ceiling and a lamp cover covering the LED light bulb, and asocket for attaching the base of the LED light bulb is provided in theequipment body. Power is supplied to the LED light bulb through thesocket.

Those skilled in the art will readily appreciate that many modificationsare possible in the exemplary embodiments without materially departingfrom the novel teachings and advantages of this invention. Accordingly,all such modifications are intended to be included within the scope ofthis invention.

INDUSTRIAL APPLICABILITY

The light bulb shaped lamp according to the present invention reproducesthe simulated filament of the incandescent light bulb by thelight-emitting device such as the LED chips and the base board. Thepresent invention is particularly effective for a light bulb shaped lampreplacing conventional incandescent light bulbs, and particularly alight bulb shaped lamp replacing the incandescent light bulb fordecorative purpose showing the filament.

REFERENCE SIGNS LIST

1, 2 LED light bulb

100, 200, 300, 400, 500, 600, 700 Filament part

110, 210, 310 LED chip

111 Sapphire board

112 Nitride semiconductor layer

113 Cathode electrode

114 Anode electrode

115, 116 Wire bonding part

117 Gold wire

118 Chip bonding material

120, 220, 320, 420, 421, 422, 423, 520, 521, 522, 523, 620, 720 Baseboard

121, 122, 321, 322 Power supply terminal

125, 225 First main surface

126, 226 Second main surface

130, 230, 330, 430, 530, 630, 730 Sealing material

140, 141, 142, 340, 341, 342 Power supply lead

160, 360 Stem

170, 370 Globe

180, 380 Circuit

181, 381 Input terminal

182, 382 Output terminal

183 Diode bridge

184 Capacitor

185, 383 Resistor

186, 385, 386 LED chip row

190, 390 Base

191 Screw part

192 Eyelet

221, 222 Through hole

223 Metal line pattern

425 Inner area

What is claimed is:
 1. A light bulb shaped lamp comprising: a base board; a light-emitting device mounted on said base board; a base for receiving power from outside; at least two power-supply leads for supplying power to said light-emitting device; and a globe for housing said base board, said light-emitting device, and said power-supply leads, said globe being partially attached to said base, wherein said base board is translucent, each of said two power-supply leads is extended from a side of said base toward inside of said globe and is connected to said base board, and said light-emitting device is provided between (i) a portion at which one of said two power-supply leads and said base board are connected and (ii) a portion at which the other of said two power-supply leads and said base board are connected. 